EPR of trivalent chromium centers with monoclinic symmetry in SrF2 crystals

Manifestation of the Jahn–Teller effect subject to quadratic T⊗e+t2 problem in ultrasonic attenuation. Case study of CaF2:Cr crystal with isovalent and aliovalent substitution

“…The anomaly cased by Cr 3+ F − 8 complexes overlaps with the region of activation relaxation of the Cr 2+ F − 8 sub-system. By analogy with Cr 3+ in SrF 2 matrix [49] we propose that in our crystal, every Cr 3+ F − 8 complex is distorted along one of the tetragonal axes due to F − compensator located in the neighboring cubic cave. This distortion has electrostatic, non-JT nature but lead to elongation (contraction) of the edges and diagonals of the complexes.…”

“…In cubic coordination, Cr 2+ ion has ground orbital triplet 5 T 2g (t 2 2g e 2 g ) (see table 1 in [33]), so the APES should be a function of [38]. However, aliovalent substitution is also possible and some papers report properties of Cr 3+ ions in the fluorite-type matrix [47][48][49]. Ultrasonic experiments were done at Ural Federal University.…”